Can someone help me with this?

D

dnorr

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Feb 9, 2011
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The manager of a mutual fund placed 30% of the fund's available cash in a 6% simple interest account, 25% in 8% corporate bonds, and the remainder in a money market fund that earns 7.5% annual simple interest. The total annual interest from the investments was $35,875. What was the total amount invested?

Here’s what I got....

(0.30x)(0.06) = 0.018x + (0.25x)(0.08) = 0.02x + (0.45x)(0.075) = 0.03375x
0.018x + 0.02x + 0.03375x = 35,875
0.07175x = 35,875
X = ????

.07 ÷ 35,875 on a calculator reads-------> 512,500

Long division says....

Code: 
     512670 <------- Did I do something wrong here?
    ----------
7 / 3587500
   -35
     ---------
     08
    - 7
     --------
      18
    - 14
      -------
       47
     - 42
       -------
        55
      - 49
        --------
         R6
 
dnorr said:
The manager of a mutual fund placed 30% of the fund's available cash in a 6% simple interest account, 25% in 8% corporate bonds, and the remainder in a money market fund that earns 7.5% annual simple interest. The total annual interest from the investments was $35,875. What was the total amount invested?

Here’s what I got....

(0.30x)(0.06) = 0.018x + (0.25x)(0.08) = 0.02x + (0.45x)(0.075) = 0.03375x
0.018x + 0.02x + 0.03375x = 35,875
0.07175x = 35,875
X = ????

.07 ÷ 35,875 on a calculator reads-------> 512,500 <<< It should have been written as 35,875 ÷ .07

Nevertheless, as far as I can see, your long division is correct.

However, the actual problem should have been

35,875 ÷ 0.07175

Then you geta nice round number as answer (500,000)

Long division says....

Code: 
     512670 <------- Did I do something wrong here?
    ----------
7 / 3587500
   -35
     ---------
     08
    - 7
     --------
      18
    - 14
      -------
       47
     - 42
       -------
        55
      - 49
        --------
         R6
Click to expand...
 
dnorr said:
Code: 
     512670 <------- Did I do something wrong here?
    ----------
7 / 3587500
   -35
     ---------
     08
    - 7
     --------
      18
Click to expand...
YES, you did something wrong; that should be 512500.
You carried down the "8" twice; last figure of 18 shown above should be 17.
Subhotosh is right now heading for the corner for telling you it was right!

Btw, I sure wish you'd STOP this long division thing SOON.
Why the heck are you not simply using your calculator...like everyone else...?

Anyway, with .07175x = 35875, the division should be
3587500000 / 7175, not 3587500 / 7
 
dnorr said:
The manager of a mutual fund placed 30% of the fund's available cash in a 6% simple interest account, 25% in 8% corporate bonds, and the remainder in a money market fund that earns 7.5% annual simple interest.
The total annual interest from the investments was $35,875. What was the total amount invested?
Here’s what I got....
(0.30x)(0.06) = 0.018x + (0.25x)(0.08) = 0.02x + (0.45x)(0.075) = 0.03375x
0.018x + 0.02x + 0.03375x = 35,875
0.07175x = 35,875
X = ????
Click to expand...
Next time you try something similar, I suggest you go this way:
Let x = total amount invested : you were told to do this before...

Interest @ 6% = .30x(.06) = .018x
Interest @ 8% = .25x(.08) = .02x
Interest @ 7.5% = .45x(.075) = .03375x

.018x + .02x + .03375x = 35875
.07175x = 35875
x = 35875 / .07175 = 500,000

Now STOP!
I'm trying to tell you that something like what I did above will
keep you on the good side of your teacher :idea:
 
I'm using long division because I have to take an exam soon giving similar problems and we are not permitted to use a calculator. Is there an easier way without a calculator? I would sure like to know.
 
Denis said:
dnorr said:
The manager of a mutual fund placed 30% of the fund's available cash in a 6% simple interest account, 25% in 8% corporate bonds, and the remainder in a money market fund that earns 7.5% annual simple interest.
The total annual interest from the investments was $35,875. What was the total amount invested?
Here’s what I got....
(0.30x)(0.06) = 0.018x + (0.25x)(0.08) = 0.02x + (0.45x)(0.075) = 0.03375x
0.018x + 0.02x + 0.03375x = 35,875
0.07175x = 35,875
X = ????
Click to expand...
Next time you try something similar, I suggest you go this way:
Let x = total amount invested : you were told to do this before...

Interest @ 6% = .30x(.06) = .018x
Interest @ 8% = .25x(.08) = .02x
Interest @ 7.5% = .45x(.075) = .03375x

.018x + .02x + .03375x = 35875
.07175x = 35875
x = 35875 / .07175 = 500,000

Now STOP!
I'm trying to tell you that something like what I did above will
keep you on the good side of your teacher :idea:
Click to expand...

x = 35875 / .07175 =

Does'nt this get a little complicated in an exam using long division? Rember, I'm not allowed to use a calculator in the exam.
 
dnorr said:
[
x = 35875 / .07175 =
Does'nt this get a little complicated in an exam using long division? Rember, I'm not allowed to use a calculator in the exam.
Click to expand...
IF IF IF... you get a division similar to this to be done by hand on a "timed exam",
then whoever set the exam should be shot at sunrise...
Anyway, this is not a concern to be addressed here: talk to your teacher/tutor/whatever...

Just my opinion...
 
Denis said:
dnorr said:
[
x = 35875 / .07175 =
Does'nt this get a little complicated in an exam using long division? Rember, I'm not allowed to use a calculator in the exam.
Click to expand...
IF IF IF... you get a division similar to this to be done by hand on a "timed exam",
then whoever set the exam should be shot at sunrise...Or hung upside down by their toes....Or sent to the corner so that I can get out.....
Anyway, this is not a concern to be addressed here: talk to your teacher/tutor/whatever...

Just my opinion...
Click to expand...
 
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